Antimicrobial coatings formed from mixtures of silanes and amines

ABSTRACT

An anti-microbial coating formulation consisting essentially of triethanolamine and a silane.

CROSS-REFERENCED TO RELATED APPLICATIONS

This application is a continuation of, claims priority to and the benefit of, U.S. Ser. No. 15/041,974, filed Feb. 11, 2016 and entitled ANTI-MICROBIAL COATING AND METHOD TO FORM SAME. The '974 application is continuation of, claims priority to and the benefit of, U.S. Ser. No. 14/932,840, filed Nov. 4, 2015 and entitled COMPOSITION AND METHOD TO FORM A SELF-DECONTAMINATING SURFACE. The '974 application also claims priority to, and the benefit of, U.S. Provisional Application No. 62/114,998 filed Feb. 11, 2015 and entitled ANTI-MICROBIAL COATING AND METHOD TO FORM SAME. The '840 application claims priority to, and the benefit of, U.S. Provisional Application No. 62/075,020 filed Nov. 4, 2014 and entitled COMPOSITION AND METHOD TO FORM A SELF-DECONTAMINATING SURFACE. All of the aforementioned applications are incorporated herein by reference in their entirety.

FIELD

Embodiments generally relate an anti-microbial coating composition, and a method using that coating composition. In certain embodiments, the coating composition comprises a photocatalyst. In certain embodiments, the photocatalyst comprises a titanyl-oxide moiety. In certain embodiments, the coating composition comprises a silane.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood from a reading of the following detailed description taken in conjunction with the drawings in which like reference designators are used to designate like elements, and in which:

FIG. 1 graphically shows the number of hospital acquired C-difficile infections in the Glendale Memorial Hospital ICU from January 2012 through February 2014;

FIG. 2 graphically shows the number of hospital acquired C-difficile infections at the Glendale Memorial Hospital (excluding ICU) from January 2012 through February 2014;

FIG. 3 shows a flowchart of a synthetic procedure for both Peroxotitanium acid solution and Peroxo-modified anatase sol;

FIG. 4 shows a table of CFU/mL data for each of three coating formulations, wherein each formulation did not include one or more titanium-oxide moieties;

FIG. 5 shows a table of Log₁₀ reduction data for three formulations evaluated, wherein each formulation did not include one or more titanium-oxide moieties;

FIG. 6 shows a table of percent reduction data for three formulations utilized, wherein each formulation did not include one or more titanium-oxide moieties;

FIGS. 7-9 show tables of anti-microbial efficacy data for electrostatic spray embodiments; and

FIGS. 10-12 show tables of anti-microbial efficacy data for non-electrostatic spray embodiments.

DETAILED DESCRIPTION

This invention is described in preferred embodiments in the following description with reference to the Figures, in which like numbers represent the same or similar elements. Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

The described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are recited to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

In certain embodiments of Inventors' composition and method, a coating is formed on a surface, where that coating comprises a plurality of silicon-oxygen bonds. In certain embodiments of Inventors' composition and method, a coating is formed on a surface, where that coating comprises a plurality of titanium-oxygen bonds in combination with a plurality of silicon-oxygen bonds.

In certain embodiments, a coating comprising a plurality of titanyl-oxide bonds in combination with a plurality of silicon-oxygen bonds is formed by disposing on a surface a silane in combination with one or more compounds comprising one or more titanyl-oxygen bonds. In certain embodiments, a coating comprising a plurality of titanyl-oxide bonds in combination with a plurality of silicon-oxygen bonds is formed by first disposing one or more compounds comprising one or more titanyl-oxygen bonds on the surface, and by disposing a silane onto the surface and over the one or more compounds comprising one or more titanyl-oxygen bonds. In certain embodiments, a coating comprising a plurality of titanyl-oxide bonds in combination with a plurality of silicon-oxygen bonds is formed by simultaneously disposing one or more compounds comprising one or more titanyl-oxygen bonds and a silane onto the surface.

In certain embodiments, Inventors' silane comprises compound 1.

In certain embodiments, R1 is selected from the group consisting of OH and O-Alkyl. In certain embodiments, R2 is selected from the group consisting of OH and O-Alkyl. In certain embodiments, R3 is selected from the group consisting of OH and O-Alkyl. In certain embodiments, R4 is selected from the group consisting of OH, O-Alkyl, Alkyl, substituted Alkyl including γ-chloro-propyl, γ-amino-propyl, and quarternary ammonium salt-substituted Alkyl.

In certain embodiments, Inventors' silane comprises a trihydroxy silane 2.

In certain embodiments, Inventors' silane comprises a silanetriol 2, wherein R4 is alkyl. In other embodiments, Inventors' silane comprises a silanetriol 2, wherein R4 is alkyl with an amino moiety. In yet other embodiments, Inventors' silane comprises a silanetriol 2, wherein R4 is alkyl with a chlorine substituent. In still other embodiments, Inventors' silane comprises a silanetriol 2, wherein R4 is alkyl with a quarternary ammonium group.

A silsesquioxane is an organosilicon compound 3 where Si represents the element silicon and O represents the element oxygen.

In certain embodiments, after application of Inventors' silane 1 or 2 to either a hard surface, i.e. wall, door, table, and the like, or a soft surface, i.e. bedding, draperies, furniture cushions, and the like, a resulting coating disposed on the hard surface/soft surface comprising a plurality of silsesquioxane structures. In certain embodiments, after application of Inventors' silane 1 or 2, in combination with one or more compounds comprising a titanyl-oxygen moiety, to either a hard surface, i.e. wall, door, table, and the like, or a soft surface, i.e. bedding, draperies, furniture cushions, and the like, a resulting coating disposed on the hard surface/soft surface comprises a plurality of silsesquioxane structures 3 in combination with plurality of titanyl-oxide structures.

Oxidation is a loss of electrons or an increase in oxidation state by a molecule, atom or ion. Substances that have the ability to oxidize other substances are said to be oxidative or oxidizing and are known as oxidizing agents, oxidants, or oxidizers. Put another way, the oxidant removes electrons from another substance, and is thus itself reduced. And, because it “accepts” electrons, it is also called an electron acceptor.

In chemistry, photocatalysis is the acceleration of a photoreaction in the presence of a catalyst. In catalyzed photolysis, light is absorbed by an adsorbed substrate. In photogenerated catalysis, the photocatalytic activity (PCA) depends on the ability of the catalyst to create electron-hole pairs, which generate free radicals (hydroxyl radicals: .OH) able to undergo secondary reactions. Its comprehension has been made possible ever since the discovery of water electrolysis by means of the titanium dioxide.

Certain titanyl-oxide morphologies exhibit photocatalytic characteristics when exposed to Ultra Violet (UV) light. When exposed to UV light, Inventors' Titanyl-Oxide Moieties create electron-hole pairs which generate free radical (e.g., hydroxyl radicals). The degree of photocatalytic strength varies depending on the type of titanyl-oxide, for example anatase titanium oxide (particle size of about 5 to 30 nanometers) is a stronger photocatalyst than rutile titanium oxide (particle size of about 0.5 to 1 microns).

In certain embodiments of Inventors' composition and method, a coating is formed on a surface, where that coating comprises a plurality of titanyl-oxide bonds, where that coating is formed by disposing Inventors' Titanyl-Oxide Moieties onto a target surface.

In certain embodiments of Inventors' composition and method, a coating is formed on a surface, where that coating comprises a plurality of silicon-oxygen bonds, where that coating is formed by disposing Inventors' silane 1 onto the surface.

In certain embodiments of Inventors' composition and method, a coating is formed on a surface, where that coating comprises a plurality of titanyl-oxide bonds, where that coating is formed by disposing on the surface a mixture of Peroxotitanium acid solution and Peroxo-modified anatase sol (collectively “Titanyl-Oxide Moieties”).

In certain embodiments, Inventors' Titanyl-Oxide Moieties comprises up to about a total of one weight percent loading of the mixture of Peroxotitanium acid solution and Peroxo-modified anatase sol. In certain embodiments, Inventors' Titanyl-Oxide Moieties comprises about 0.5 weight percent Peroxotitanium acid solution in combination with about 0.5 weight percent Peroxo-modified anatase sol.

A method to prepare both Peroxotitanium acid solution and Peroxo-modified anatase sol is disclosed in Journal of Sol-Gel Science and Technology, September 2001, Volume 22, Issue 1-2, pp 33-40. This publication discloses, inter alia, the reaction scheme, shown in FIG. 3, which summarizes the synthetic procedure for both Peroxotitanium acid solution and Peroxo-modified anatase sol.

In the following examples, reference is made to coatings ABS-G2015, ABS-G2020, and ABS-G2030. Coating formulation ABS-G2015 comprises a silicone-containing compound having structure V:

Coating formulation ABS-G2015 further comprises the Titanyl-Oxide Moieties. The order of deposition onto a surface is not critical. In certain embodiments, the silicone-containing compound is first disposed on a surface, and the Titanyl-Oxide Moieties are disposed over that silicone-containing compound. In other embodiments, the Titanyl-Oxide Moieties are first disposed on a surface, and the silicone-containing compound is disposed over that Titanyl-Oxide Moieties-treated surface. In yet other embodiments, the Titanyl-Oxide Moieties and the silicone-containing compound are first pre-mixed, and the resulting mixture is disposed on the surface of the substrate.

Coating formulation ABS-G2020 comprises a silicone-containing compound having structure VI:

Coating formulation ABS-G2020 further comprises the Titanyl-oxide Moieties. The order of deposition onto a surface is not critical. In certain embodiments, the silicone-containing compound is first disposed on a surface, and the Titanyl-oxide Moieties are disposed over that silicone-containing compound. In other embodiments, the Titanyl-oxide Moieties are first disposed on a surface, and the silicone-containing compound is disposed over that Titanyl-oxide Moieties-treated surface. In yet other embodiments, the Titanyl-oxide Moieties and the silicone-containing compound are first pre-mixed, and the resulting mixture is disposed on the surface of the substrate.

Coating formulation ABS-G2030 comprises a silicone-containing compound having structure VII:

Coating formulation ABS-G2030 further comprises the Titanyl-Oxide Moieties. The order of deposition onto a surface is not critical. In certain embodiments, the silicone-containing compound is first disposed on a surface, and the Titanyl-Oxide Moieties are disposed over that silicone-containing compound. In other embodiments, the Titanyl-Oxide Moieties are first disposed on a surface, and the silicone-containing compound is disposed over that Titanyl-Oxide Moieties-treated surface. In yet other embodiments, the Titanyl-Oxide Moieties and the silicone-containing compound are first pre-mixed, and the resulting mixture is disposed on the surface of the substrate.

The following Examples are presented to further illustrate to persons skilled in the art how to make and use the invention. These Examples are not intended as limitations, however, upon the scope of the invention.

Example 1

This Example 1 evaluates the anti-microbial efficacy of coatings ABS-G2015, ABS-G020, and ABS G-2030, against Murine Noro Virus. Murine norovirus (MNV) is a species of norovirus affecting mice. Norovirus is the most common cause of viral gastroenteritis in humans. It affects people of all ages. The virus is transmitted by, inter alia, aerosolization of the virus and subsequent contamination of surfaces. The virus affects around 267 million people and causes over 200,000 deaths each year, these deaths are usually in less developed countries and in the very young, elderly and immunosuppressed.

The test coupons of this Example 1 were prepared using the Procedure recited immediately hereinbelow.

Procedure

Put on sterile gloves.

Prepare the test coupons by wiping them first with Isopropyl Alcohol and allowing to dry.

Clean the test coupons with surface cleaner using a microfiber cloth.

Hold sprayer about eight (8) inches from surface to be cleaned.

Spray on let stand for 1-3 minutes and wipe it off, if the area is extremely dirty allow cleaner to stand longer, or apply a second spray and wipe.

Wipe surface with a clean, damp sponge or cloth.

Allow surface to completely dry.

With gloved hands examine coupons for consistency.

Prepare a 10 volume percent solution of the selected silane in Methanol (MeOH) (10 ml silane in 90 ml MeOH).

Prepare Triethanolamine as a 10 volume percent solution in MeOH.

Combine the triethanolamine solution and the silane solution in a 1:1 ratio on a stir plate at room temperature (ie-100 ml triethanolamine solution added to 100 ml silane solution).

Silane Application

Add the 1:1 silane/triethanolamine solution described above to the applicator container.

Fasten the Liquid Hose/Bottle cap assembly tightly on the container.

Connect the air hose from compressor to air fitting on the spray applicator.

Connect the liquid hose to the liquid fitting on the spray applicator.

Plug the power cord into an appropriate receptacle. Turn on the air compressor.

Optimal spraying distance is at least 36 to 48 inches away from the target surface.

Hold the spray gun at right angles to the target surface and spray.

Target surface should just barely glisten with the spray. Do not over-saturate the surface.

Allow target surface to dry, i.e. allow at least 90 weight percent of the methanol liquid carrier to evaporate to give a deposition consisting essentially of the selected silane and triethanolamine. The deposition onto the target surface consists of at least 33 volume percent of the selected silane, at least 33 volume percent of triethanolamine, and up to about 33 volume percent residual methanol carrier liquid.

Rinse spray gun with distilled water prior to applying Inventors' Titanyl-Oxide Moieties (unless using 2 sprayers, one for each product).

Titanyl-Oxide Moieties Application

Add an aqueous mixture of Inventors' Titanyl-Oxide Moieties to the applicator container.

Fasten the Liquid Hose/Bottle cap assembly tightly on the container.

Connect the air hose from compressor to air fitting on the spray applicator.

Connect the liquid hose to the liquid fitting on the spray applicator.

Plug the power cord into an appropriate receptacle. Turn on the air compressor.

Optimal spraying distance is at least 36 to 48 inches away from the target surface.

Hold the spray gun at right angles to the target surface and spray.

Target surface should just barely glisten with the spray. Do not over-saturate the surface.

Allow target surface to dry, i.e. allow at least 90 weight percent of the water liquid carrier to evaporate to give a deposition consisting essentially of Inventors' Titanyl-Oxide Moieties. The deposition onto the target surface consists of at least 66 volume percent of Inventors' Titanyl-Oxide Moieties and up to about 33 volume percent residual water carrier liquid.

Clean the spray gun with distilled water per manufactures' specifications after each day of use.

Tables 2 and 3 recite anti-microbial efficacy data four (4) hours after inoculation of the treated test coupons. Table 2 includes data for ABS-G2020 and ABS-G2030 treated Formica coupons. Table 3 includes data for ABS-G2020 and ABS G-2030 treated stain less steel coupons.

TABLE 1 Surface Time-Kill Study Evaluating Four Coating Formulations Against Murine Norovirus: Time Zero Data Con- Viral Counts Log₁₀ Percent Test tact (TCID₅₀ Reduc- Reduc- Organism Time Sample ID^(a) per mL) tion tion Murine Time Zero Formica - Ctrl 1.48E+07 N.A. norovirus SS-Ctrl 6.76E+06 ^(a)SS: Stainless Steel

TABLE 2 Surface Time-Kill Study Evaluating Four Coating Formulations Against Murine Norovirus: 4 Hour Contact Time Data Con- Viral Counts Log₁₀ Percent Test tact (TCID₅₀ Reduc- Reduc- Organism Time Sample ID^(a) per mL) tion tion Murine 4 Hours Ctrl (Formica) 1.00E+05 N.A. norovirus Ctrl (SS) 6.76E+04 ABS-G2015 6.76E+04 0.00    0% (SS) ABS-G2020 ≤3.16E+03  ≥1.50 ≥97% (Form) ABS-G2030 6.76E+03 1.00  90% (Form)

TABLE 3 Surface Time-Kill Study Evaluating Two Coating Formulations Against Murine Norovirus: 4 Hour Contact Time Data Log₁₀ Percent Log₁₀ Percent Reduction Reduction Viral Counts Reduction Reduction Relative to Relative to Test Contact (TCID₅₀ Mean Viral Relative to Relative to Timed Timed Organism Time Sample ID^(a) per mL) Titer^(b) Time Zero Time Zero Control Control Murine 4 Hours SS - Control (Rep A) 6.76E+04 1.06E+05 1.47     97% N.A. norovirus SS - Control (Rep B) 1.45E+06 ABS-G2020 (Rep A) 1.00E+04 1.57E+04 2.30  99.5% 0.83 85.2% ABS-G2020 (Rep B) 2.14E+04 ABS-G2030 (Rep A) 4.68E+03 ≤3.92E+03  ≥2.91 ≥99.8% ≥1.43 ≥96.3% ABS-G2030 (Rep B) ≤3.16E+03  ^(a)SS: Stainless Steel ^(b)“≤”: No viral cytopathology observed beyond toxic levels; therefore titer at or below limit of detection

TABLE 4 Surface Time-Kill Study Evaluating Two Coating Formulations Against Murine Norovirus: 6 Hour Contact Time Data Log₁₀ Percent Log₁₀ Percent Reduction Reduction Viral Counts Reduction Reduction Relative to Relative to Test Contact (TCID₅₀ Mean Viral Relative to Relative to Timed Timed Organism Time Sample ID^(a) per mL) Titer^(b) Time Zero Time Zero Control Control Murine 6 Hours SS - Control (Rep A) 3.16E+04 4.96E+04 1.80     98% N/A. norovirus SS - Control (Rep B) 6.76E+04 ABS-G2020 (Rep A) 1.00E+04 8.38E+03 2.58  99.7% 0.77 83.1% ABS-G2020 (Rep B) 6.76E+03 ABS-G2030 (Rep A) 4.68E+03 ≤3.92E+03  ≥2.91 ≥99.8% ≥1.10 ≥92.1% ABS-G2030 (Rep B) ≤3.16E+03  ^(a)SS: Stainless Steel ^(b)“≤”: No viral cytopathology observed beyond toxic levels; therefore titer at or below limit of detection

-   -   1. RAW (mouse macrophage) host cells were prepared in 96-well         trays 24 hours prior to use in testing.     -   2. On the day of testing, a stock vial of test virus, murine         norovirus, was removed from storage at −80° C. (titer=5×10⁸         TCID₅₀ units per ml). An organic soil load (heat-inactivated         fetal bovine serum) was added to obtain a final concentration of         5%.     -   3. Control (non-coated stainless steel and formica) and coated         test carriers [ABS-G2015 (SS); ABS-G2020 (Form); ABS-G2030         (Form); ABS-P2015 (SS)] were placed into sterile Petri dishes         (one per dish) using pre-sterilized forceps.     -   4. Viral inocula (0.010 ml) were pipetted onto the center of the         control and test carriers, and spread over a surface area of         ˜1-in² using a sterile, bent pipette tip.     -   5. One set of control carriers (per surface material type) was         harvested/neutralized immediately to determine Time Zero counts         by placement into sterile stomacher bags containing 3 ml of         neutralizing solution (calf scrum supplemented with 0.001%         Na-thiosulfate and 0.001% Na-thioglycollate). The bags were         stomached for 120 seconds at high speed to release the viruses         from the carriers.     -   6. The remaining control and test carriers were held under         ambient conditions for the duration of each of the specified         study contact times of 4 hours and 24 hours [placement         distance/configuration: ˜68 inches (˜1.7 m) below two         full-spectrum bulbs, inoculated side facing up towards the         lights)]. All carriers were observed to be dried within 10         minutes of inoculation.     -   7. Upon closure of the respective contact times, the control and         test carriers were neutralized by placement into sterile         stomacher bags containing 3 ml of neutralizing solution,         followed by stomaching as previously described.     -   8. At the start and finish of each of the contact times, room         temperature, relative humidity, and illuminance (lux) were         measured and recorded.     -   9. Control and test carrier eluates were serially diluted (1:10)         and plated in replicates of six onto RAW host cells prepared to         the appropriate confluency.     -   10. The plates were observed every 24 to 48 hours to visualize         viral cytopathic effects (CPE) and cytotoxicity.     -   11. Following a 9-day assay incubation period, the plates were         formally scored.     -   12. Log₁₀ and percent reductions were calculated for each of the         test coating formulations relative to the timed control virus         counts (per surface type). However, reductions could not be         computed for the 24 hour contact time due to insufficient viral         recovery from the control carriers.     -   13. A neutralization validation was performed for each of the         test coating formulations (except for ABS-P2015 due to a lack of         carriers). One control carrier and one of each test carrier type         were placed into stomacher bags containing 3 ml of neutralizer,         and processed as previously described. The eluate was serially         diluted, and low titer inoculum of the test virus (˜3-log₁₀) was         added to each of the dilution tubes per control and test carrier         suspension. Aliquots (0.1 ml) of the suspensions were then         plated in order to assess cytotoxic levels of the neutralized         test materials.

Example 2

This Example 2 utilizes the three (3) silanes utilized in coating formulations, namely ABS-G2015, ABS-G2020, and ABS-G2030, but without any Titanyl-Oxide containing compounds. The method of Example 1 relating to spray deposition of a silane onto test coupons was utilized in this Example 2. The method of Example 1 relating to spray deposition of the Titanyl-Oxide Moieties was not utilized in this Example 2.

TABLE 5 in FIG. 4 recites CFU/mL data for each of the three coating formulations, wherein each formulation did not include one or more titanium-oxide moieties. TABLE 6 in FIG. 5 recites Log Reduction data for the three formulations evaluated, wherein each formulation did not include one or more titanium-oxide moieties. TABLE 7 in FIG. 6 recites Percent Reduction data for the three formulations utilized, wherein each formulation did not include one or more titanium-oxide moieties.

Example 3

This Example 3 utilizes complete formulations ABS-G2015, AB-G2020, and ABS-G2030, where those coating formulations were disposed on stainless steel test coupons using the full procedure of Example 1. In one set of experiments, the formulations were disposed onto the test coupons using an electrostatic spray assembly. In another set of experiments, the formulations were disposed onto the test coupons using a non-electrostatic spray assembly.

Table 8 in FIG. 7, Table 9 in FIG. 8, and Table 10 in FIG. 9, recite anti-microbial efficacy data for the electrostatic spray embodiments. Table 11 in FIG. 10, Table 12 in FIG. 11, and Table 13 in FIG. 12, recite anti-microbial efficacy data for the non-electrostatic spray embodiments.

Example 4

A study was conducted at the Glendale Memorial Hospital and Health Center in Glendale, Calif. (the “Glendale Memorial Hospital Study”). The Center has a 24 bed intensive care (ICU). The study was performed between May 10 and Sep. 30, 2013. The Glendale Memorial Hospital Study was designed to assess the anti-microbial efficacy of coating composition ABS-G2015, described hereinabove, where that coating composition was applied using the complete method of Example 1 herein.

In the Glendale Memorial Hospital Study, the entire ICU was subjected to the two step spray regime described herein to treat all surfaces in each room including hard surfaces (beds, tray tables, bed rail, walls, etc.) and soft surfaces (drapes, cloth and vinyl covered chairs, etc.). More specifically, each surface was first electrostatically spray coated at room temperature using an aqueous composition formed by mixing Octadecylaminodimethyltrihydroxysilylpropyl Ammonium Chloride (the “Silylated Quarternary Amine”) at about 3.6 weight percent in water.

After about fifteen (15) minutes after the electrostatic spray coating using the aqueous Silylated Quarternary Amine, each surface was then electrostatically coated at room temperature using the Titanyl-Oxide Moieties described hereinabove.

The treated surfaces were maintained at room temperature during the spray deposition of the aqueous Silylated Quarternary Amine, and during the spray deposition of the Titanyl-Oxide Moieties. None of the treated surfaces were subjected to any elevated heat treatment wherein the treated surface was heated to a temperature greater than about room temperature after completion of the two step coating regime.

Ninety-five (95) specific sites in the ICU were selected for recurring sampling at weeks 1, 2, 4, 8, and 15, after the two step spraying regime. Those selected sites included bed rails, bed controls, tray tables, and walls above sinks. Samples were also collected from the two ICU nursing stations and waiting lobby including countertops, phones, computer keyboards, chair armrests and end tables. All movable items were inconspicuously tagged and coded over the course of the study so that the same objects could be sampled.

Areas of 100 cm² were sampled using a sponge stick containing Letheen broth (3M, St. Paul, Minn.) to neutralize any residual disinfectant. After collection the samples were immediately placed on ice packs and sent overnight to the University of Arizona for analysis by Professor Charles Gerba.

FIG. 1 hereto is a true and accurate copy of a first graph provided by the Manager, Infection Prevention, Dignity Health/Glendale Memorial Hospital & Health Center. Exhibit 1 graphically shows the number of hospital acquired C-difficile infections in the Glendale Memorial Hospital ICU from January 2012 through February 2014.

FIG. 1 indicates that with the exception of September 2013, there were no hospital acquired C-difficile infections originating in the ICU during the period May 2013 through November 2013. Thus, FIG. 1 shows that there was a single hospital acquired C-difficile infection originating in the ICU during the six month period May 2013 through November 2013.

FIG. 1 further shows that, other than the six month period May 2013 through November 2013, there was no other 6 month period during the 25 months from January 2012 through February 2014 wherein only a single hospital acquired C-difficile infection originated in the ICU.

All surfaces in the ICU were treated as described hereinabove during the first week of May 2013 as part of the Glendale Memorial Hospital Study. FIG. 2 hereto is a true and accurate copy of a second graph provided by the Manager, Infection Prevention, Dignity Health/Glendale Memorial Hospital & Health Center. Exhibit 2 graphically shows the number of hospital acquired C-difficile infections at the Glendale Memorial Hospital (excluding ICU) from January 2012 through February 2014.

FIG. 2 indicates that, with the exception of April 2013, there were between 1 and 8 hospital acquired C-difficile infections every month during the 25 month period in hospital areas outside of the ICU. During the period May 2013 through November 2013, FIG. 2 shows that there were a total of 20 hospital acquired C-difficile infections originating outside of the ICU at the Glendale Memorial Hospital.

FIGS. 1 and 2 show that during the period May 2013 through November 2013, a single hospital acquired C-difficile infection originated in the ICU at the Glendale Memorial Hospital, and a total of 20 hospital acquired C-difficile infections originated outside of the ICU at the Glendale Memorial Hospital.

Clostridium difficile colitis or pseudomembranous colitis is colitis (inflammation of the large intestine) resulting from infection with Clostridium difficile, a type of spore-forming bacteria. It causes an infectious diarrhea called C. difficile diarrhea. Latent symptoms of Clostridium difficile infection (CDI) often mimic some flu-like symptoms and may mimic disease flare-ups in people with inflammatory bowel disease-associated colitis. C. difficile releases toxins that may cause bloating and diarrhea, with abdominal pain, which may become severe.

C. difficile is transmitted from person to person by the fecal-oral route. The organism forms heat-resistant spores that are not killed by alcohol-based hand cleansers or routine surface cleaning. Thus, these spores survive in clinical environments for long periods. Because of this, the bacteria may be cultured from almost any surface.

Clostridium difficile spores are extremely hardy, and can survive for long amounts of time in environments devoid of food. The spores are resistant to drying and heating, and also have resistance to many forms of antiseptic cleaners. C. diff can also survive in spore form for as long as five months. The ability of C. diff. to survive in this resistant form poses quite a challenge for hospitals.

Because C. diff forms heat-resistant spores that are not killed by alcohol-based hand cleansers or routine surface cleaning, the data of FIGS. 1 and 2 demonstrate that treatment of hard surfaces and soft surface in the Glendale Memorial Hospital ICU with ABS-G2015 necessarily reduced the occurrence of C. diff spores in that ICU. The data of FIG. 2 show that other hospital departments that were not treated with ABS-G2015 coating composition experienced a much greater level of hospital acquired C. diff infections, thereby corroborating the anti-microbial efficacy of the coating resulting from application of ABS-G2015 against C. diff spores.

In coating formulations ABS G2015, G2020, and G2030, depending on the stoichiometry of the mixture of triethanolamine and the organosilane, one or polymeric species are formed on a treated surface. In certain embodiments, and as shown in Reaction Scheme 2, triethanolamine 9 and organosilane 1 react to form a linear polymer 10, wherein n is greater than or equal to 1 and less than or equal to about 10.

In other embodiments, and as shown in Reaction Scheme 3, triethanolamine 9 and organosilane 1 react to form a branched polymer 11.

Wherein in Reaction Scheme 3, x is greater than or equal to 1 and less than or equal to about 10, and wherein y is greater than or equal to 1 and less than or equal to about 10.

In other embodiments, and as shown in Reaction Scheme 4, triethanolamine 9 and organosilane 1 react to form a cross-linked polymer 12.

Wherein in Reaction Scheme 4, x is greater than or equal to 1 and less than or equal to about 10, and wherein y is greater than or equal to 1 and less than or equal to about 10, and wherein z is greater than or equal to 1 and less than or equal to about 10.

In certain embodiments, Inventors' organosilane comprises tetraethylorthosilicate 13. In certain embodiments and as shown in Reaction Scheme 5 and depending on the stoichiometry of the starting materials 9 and 13, Inventors' cross-linked polymeric material 14 is formed by reaction of tetraethylorthosilicate 13 and triethanolamine 9. Reaction Scheme 5 illustrates a single Si atom having four (4) different polymer chains originating therefrom. Those skilled in the art will appreciate that Inventors' cross-linked polymer material 14 comprises a very high cross-link density.

Wherein in Reaction Scheme 5, a is greater than or equal to 1 and less than or equal to about 10, and wherein b is greater than or equal to 1 and less than or equal to about 10, and wherein c is greater than or equal to 1 and less than or equal to about 10, and wherein d is greater than or equal to 1 and less than or equal to about 10.

In certain embodiments and as shown in Reaction Scheme 6 and depending on the stoichiometry of the starting materials 15 and 13, Inventors' cross-linked polymeric material 16 is formed by reaction of tetraethylorthosilicate 13 and diethanolamine 13. Reaction Scheme 6 illustrates a single Si atom having four (4) different polymer chains originating therefrom. Those skilled in the art will appreciate that Inventors' cross-linked polymer material 16 comprises a very high cross-link density.

Wherein in Reaction Scheme 6, a is greater than or equal to 1 and less than or equal to about 10, and wherein b is greater than or equal to 1 and less than or equal to about 10, and wherein c is greater than or equal to 1 and less than or equal to about 10, and wherein d is greater than or equal to 1 and less than or equal to about 10.

While the preferred embodiments of the present invention have been illustrated in detail, it should be apparent that modifications and adaptations to those embodiments may occur to one skilled in the art without departing from the scope of the present invention. 

We claim:
 1. An antimicrobial coating, formed by a method comprising: (a) providing a mixture of: (i) an organosilane of structure (1),

wherein R1 is —H or -Alkyl; and R2 is γ-chloropropyl- or γ-aminopropyl; (ii) triethanolamine; and (iii) methanol; (b) spraying said mixture onto a substrate surface; and (c) allowing at least about 90% by weight of the methanol to evaporate from the surface to form said antimicrobial coating on said substrate.
 2. The antimicrobial coating of claim 1, wherein said substrate is stainless steel.
 3. The antimicrobial coating of claim 2, wherein R1 is —H and R2 is γ-chloropropyl, and wherein said antimicrobial coating exhibits 100.00% reduction in murine norovirus 1 hour after initial inoculation of the coating with murine norovirus.
 4. The antimicrobial coating of claim 2, wherein R1 is —H and R2 is γ-aminopropyl, and wherein said antimicrobial coating exhibits 100.00% reduction in murine norovirus 1 hour after initial inoculation of the coating with murine norovirus.
 5. The antimicrobial coating of claim 1, wherein said antimicrobial coating comprises a polymer having structure (10),

wherein n is from about 1 to about
 10. 6. The antimicrobial coating of claim 1, wherein said organosilane is tetraethylorthosilicate.
 7. An antimicrobial coating, formed by a method comprising: (a) providing a mixture of: (i) an organosilane of structure (1),

wherein R1 is —H or -Alkyl; and R2 is γ-chloropropyl- or γ-aminopropyl; (ii) diethanolamine; and (iii) methanol; (b) spraying said mixture onto a substrate surface; and (c) allowing at least about 90% by weight of the methanol to evaporate from the surface to form said antimicrobial coating on said substrate.
 8. The antimicrobial coating of claim 7, wherein said organosilane is tetraethylorthosilicate. 